.app{
	width: 100%;
	height: 100vh;
	background-color: #ffffff;
	position: relative;
	display: flex;
	justify-content: center;
	align-items: center;
}
.btn41{
	width: 140px;
	height: 50px;
	font-size: 14px;
	font-weight: 700;
	border: none;
	background-color: #2c3754;
	color: #ffffff;
	position: relative;
	cursor: pointer;
	z-index: 0;
}
.btn41:before{
	content: '';
	width: 0;
	height: inherit;
	position: absolute;
	top: 0;
	left: 0;
	background-color: darkred;
	z-index: -1;
	transition: all 0.4s;
}
.btn41:hover:before{
	width: 100%;
}